DFT Study of Adsorption of Trimetallic Endohedral Fullerenes on Graphene
A density functional theory (DFT) study on the geometric and electronic structure of C60 and Sc3N@C80 along with their adsorption on pristine single layer graphene (SLG) is presented. C 60 is found to adsorb in two nearly degenerate configurations: (i) with a pentagon facing the SLG, which is the most stable one, and (ii) with a hexagon facing the SLG in a face-to-face perfect alignment, rarely common in π–π interactions, 0.06 eV higher in energy. The calculated binding energy of 0.76 eV, which includes dispersion effects, is in good agreement with previous theoretical and experimental reports. On the contrary, Sc3N@C80 adsorption on the SLG resulted in a higher binding energy of 1.00 eV for nearly degenerate isomers that have a pentagon and a hexagon facing the SLG. This larger binding energy is explained in terms of a higher dispersion interaction between the larger metallofullerene and the SLG, and because charge separation in Sc3N@C80 results in a positively charged Sc 3N inside a negatively charged C80, and such an arrangement favors binding with the SLG. Furthermore, the Sc3N moiety is found to rotate inside the supported C80 fullerene, which in combination with the orientation of the fullerene on the SLG leads to a series of isomers with binding energies ranging from 0.76 to 1.00 eV. Sc3N@C80 adsorption distance with respect to SLG is also calculated. Our results show that it could be possible to adsorb metallofulleres on SLG with an energy large enough to prevent diffusion, therefore opening the possibility to potential applications in the future technologies.
Karle, Nakul Nitin, "DFT Study of Adsorption of Trimetallic Endohedral Fullerenes on Graphene" (2017). ETD Collection for University of Texas, El Paso. AAI10280796.